/**
 * Copyright 2006 gworks.com.au
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. (http://www.apache.org/licenses/LICENSE-2.0)
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed 
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for 
 * the specific language governing permissions and limitations under the License.
 *
 * <dhamma-message src="Atisha (11th century Tibetan Buddhist master)">
 *  The greatest achievement is selflessness. The greatest worth is self-mastery.
 *  The greatest quality is seeking to serve others. The greatest precept is continual awareness.
 *  The greatest medicine is the emptiness of everything. The greatest action is not conforming with the worlds ways.
 *  The greatest magic is transmuting the passions. The greatest generosity is non-attachment.
 *  The greatest goodness is a peaceful mind. The greatest patience is humility.
 *  The greatest effort is not concerned with results. The greatest meditation is a mind that lets go.
 *  The greatest wisdom is seeing through appearances. 
 * </dhamma-message>
 * 
 * @author Ashin Wimalajeewa (ash)
 */
package org.javaongems.rico.client;

import com.google.gwt.user.client.Timer;

public class Transition extends Timer {
	static public interface Effect {
		public void start();
		public void transition(int step, int remainingSteps, int stepDuration);
		public void end();
		public void reverse();
		public boolean isForward();
		public void abort();
		public boolean isAborted();
		public EffectEventListener getListener();
	}
	
	static public interface EffectEventListener {
		public void onStart(Effect sender);
		public void onStepCompleted(Effect sender, int step, int remainingSteps, int stepDuration);
		public void onEnd(Effect sender);
		public void onAbort(Effect sender);
	}
	
	private Effect effect;
	private int duration, steps, step;
	
	private Transition(Effect eff, int dur, int stps) {
		effect = eff;
		duration = dur;
		steps = stps;
	}
	
	static public void run(Effect st, int dur, int steps) {
		Transition eff = new Transition(st, dur, steps);
		st.start();
		EffectEventListener listener = st.getListener();
		if (listener != null)
			listener.onStart(st);
		eff.schedule(1);
	}

	public void run() {
		EffectEventListener listener = effect.getListener();
		if (effect.isAborted()) {
			if (listener != null)
				listener.onAbort(effect);
			return;
		}
		if (steps <=0) {
			effect.end();
			if (listener != null)
				listener.onEnd(effect);
			return;
		}
		int stepDuration = Math.round(duration/steps);
		effect.transition(step, steps, stepDuration);
	    if (listener != null)
	    	listener.onStepCompleted(effect, step, steps, stepDuration);
		step++; steps--;
	    duration -= stepDuration;
	    schedule(stepDuration);
	}
}